The known master cylinders for hydraulic disk brakes usually contain a compensating chamber for hydraulic medium so that hydraulic medium from the compensating chamber can flow into the rest of the braking system when the brake pad wear increases. In addition, it is possible to balance changes in volume caused in particular by temperature fluctuations, where such changes can occur in powerful and long braking operations in which the hydraulic medium can get hot.
Braking systems that have a compensating chamber for hydraulic medium are referred to as open systems. In the known master cylinders, a piston is movably disposed in a cylindrical chamber. A pressure chamber is provided in the cylindrical chamber and is confined by the piston. The pressure chamber is connected to the compensating chamber through a connecting opening. The connection between the pressure chamber and the compensating chamber can be interrupted through a gasket (primary gasket) as soon as the secondary gasket travels over the connecting opening as a result of the piston movement.
A gasket (secondary gasket) is provided between the piston and the cylinder wall of the cylindrical chamber and seals the pressure chamber and the compensating chamber against the environment.
The pressure chamber is connected to a slave (in the case of disk brakes: the brake caliper) through a pressure line. The hydraulic medium is pressurized by the movement of the piston along the main axis of the cylinder as soon as the connection between the pressure chamber and the compensating chamber is interrupted.
The known master cylinders have the drawback that they are made so as to have a relatively elongated design along the cylinder axis, which is due to the necessity of providing both a primary gasket and a secondary gasket. As a result, the master cylinder is relatively large and heavy. Particularly in the case of radial mountings where the cylinder axis extends perpendicularly to the axis of the handlebar and/or of inclined radial mountings in which the cylinder axis extends at an angle of less than 90 degrees, this yields a relatively large installation space and, thus, results in a relatively large distance between the handlebar and the center of rotation about which the lever of the brake fitting rotates when the master cylinder is actuated.
Thus, a need exists to overcome the problems with the prior art systems, designs, and processes as discussed above.